Method for the preparation of acryloxy-functional or methacryloxy-functional organosilcon compounds

ABSTRACT

A method for making (meth)acryloxy-functional organosilicon compounds comprising conducting an addition reaction between 
     (A) an acrylate ester or methacrylate ester of an aliphatically unsaturated alcohol and 
     (B) a SiH-functional organosilicon compound in the presence of 
     (C) a hydrosilylation-reaction catalyst and 
     (D) a compound described by general formula ##STR1## where A is a (N,N-dialkylamino)alkyl and R is a monovalent hydrocarbon group or a hydrogen atom. The presence of component (D) in the present method inhibits the generation of reaction by-products and prevents gelation during the addition reaction and very efficiently produces high-purity (meth)acryloxy-functional organosilicon compounds in high yields.

BACKGROUND OF INVENTION

This invention relates to methods for the preparation ofacryloxy-functional or methacryloxy-functional organosilicon compounds.More particularly, this invention relates to a very efficient method forthe preparation of high-purity acryloxy-functional ormethacryloxy-functional organosilicon compounds in which the generationof reaction by-products is inhibited and gelation of the reactionproduct does not occur.

Organosilicon compounds functionalized with the acryloxy or methacryloxygroup (hereinafter abbreviated as (meth)acryloxy-functionalorganosilicon compounds) readily react with radically-polymerizablemonomers, e.g., methyl methacrylate and styrene, and as a consequenceare used as starting materials for copolymers deriving from thesemonomers and as modifiers for polymers obtained from these monomers.

These (meth)acryloxy-functional organosilicon compounds are prepared byaddition-reacting the acrylate ester or methacrylate ester of analiphatically unsaturated alcohol with a SiH-functional halosilane andsubsequently isolating the (meth)acryloxy-functional organosiliconcompound from the reaction mixture by distillative purification (Refer,for example, to Japanese Patent Application Laid Open (Kokai) Number Hei5-301881 (301,881/1993)). However, these addition reactions arefrequently accompanied by the generation of reaction by-products such asacrylic acid and methacrylic acid. Moreover, since these reactionby-products as well as the (meth)acryloxy-functional compounds arereadily polymerize upon heating, these methods are also oftenaccompanied by polymerization to high molecular weight compounds andgelation during the addition-reaction stage and during the distillationstep. As a consequence, the addition reactions in these methods must berun while maintaining the reaction temperature at a level at whichthermal polymerization will not occur. This type of temperature controlis quite difficult, however, and the reaction products still oftenundergo polymerization to high molecular weights and gelation.

Japanese Patent Application Laid Open (Kokai) Number Hei 5-186478(186,478/1993) discloses a method that usesN,N,-dialkylaminomethylenephenol as polymerization inhibitor. Thisinhibitor has relatively good effects in terms of inhibiting thepolymerization of acrylic-functional silane and halosilane, but it is apoison of the platinum catalysts used as addition-reaction catalysts inthe synthesis of these silanes by addition reaction as described above.This method thus suffers from the problem of requiring the use of largeamounts of platinum catalyst to complete the reaction.

As a result of extensive investigations directed to solving the problemsdescribed above, the inventors have discovered that running the subjectaddition reaction in the presence of a special type of compound inhibitsthe generation of reaction by-products and prevents gelation during theaddition reaction. Specifically, the object of the present invention isto provide a high-yield method for the synthesis of high-purity(meth)acryloxy-functional organosilicon compounds in which during theproduction of these compounds the generation of reaction by-products isinhibited and gelation of the reaction mixture does not occur.

SUMMARY OF INVENTION

The present invention comprises running the addition reaction between

(A) an acrylate ester or methacrylate ester of an aliphaticallyunsaturated alcohol and

(B) a SiH-functional organosilicon compound in the presence of

(C) a hydrosilylation-reaction catalyst and

(D) a compound described by general formula ##STR2## where A is a(N,N-dialkylamino)alkyl and R is a monovalent hydrocarbon group or ahydrogen atom. The presence of component (D) in the present methodinhibits the generation of reaction by-products and prevents gelationduring the addition reaction and very efficiently produces high-purity(meth)acryloxy-functional organosilicon compounds in high yields.

DESCRIPTION OF INVENTION

The present invention is a method for the preparation ofacryloxy-functional or methacryloxy-functional organosilicon compoundscomprising the addition reaction between

(A) an acrylate ester or methacrylate ester of an aliphaticallyunsaturated alcohol and

(B) a SiH-functional organosilicon compound in the presence of

(C) a hydrosilylation-reaction catalyst and

(D) a compound described by general formula ##STR3## where A is(N,N-dialkylamino)alkyl and R is a monovalent hydrocarbon group or ahydrogen atom.

The acrylate ester of an aliphatically unsaturated alcohol (A) used inthe present method is exemplified by allyl acrylate, hexenyl acrylate,allyloxyethyl acrylate, and 4-vinylphenyl acrylate. The methacrylateester of an aliphatically unsaturated alcohol is exemplified by allylmethacrylate, hexenyl methacrylate, allyloxyethyl methacrylate, and4-vinylphenyl methacrylate.

The SiH-functional organosilicon compound (B) used in the present methodis not particularly restricted other than that the product afforded bythe addition reaction of (B) with component (A) should have a boilingpoint in a temperature range capable of distillation. Component (B) isexemplified by trichlorosilane, methyldichlorosilane,dimethylchlorosilane, trimethoxysilane, methyldimethoxysilane,dimethylmethoxysilane, pentamethyldisiloxane, and1,1,2,2-tetramethyldisiloxane. Component (B) is preferably used at from0.8 to 1.2 equivalents per equivalent of component (A).

The hydrosilylation-reaction catalyst (C) used in the present method ispreferably a transition metal catalyst from Group VIII of the PeriodicTable, among which platinum catalysts are the most preferred. Usefulplatinum catalysts are exemplified by alcohol solutions ofchloroplatinic acid, platinum-olefin complexes, and platinum complexeswith vinyl-functional siloxane. Component (C) is preferably used at from0.1 to 200 weight-ppm platinum, based on the total quantity ofcomponents (A) and (B).

Component (D) used in the present method is the component thatcharacterizes the present invention. This component functions to inhibitthe generation of by-products that may be produced during the additionreaction between components (A) and (B) and to prevent the reactionproduct from polymerizing to high molecular weights and gelling.

Component (D) is a (N,N-dialkylamino)alkyl-functional compound describedby general formula ##STR4## where R is the hydrogen atom or a monovalenthydrocarbon group such as methyl, ethyl, and propyl. The group A is a(N,N-dialkylamino)alkyl and is exemplified by dimethylaminoethyl,diethylaminoethyl, dimethylaminopropyl, and diethylaminopropyl.Component (D) is specifically exemplified by (N,N-dimethylamino)ethylacrylate, (N,N-diethylamino)ethyl acrylate, (N,N-dimethylamino)propylacrylate, (N,N-dimethylamino)ethyl methacrylate, (N,N-diethylamino)ethyl methacrylate, and (N,N-dimethylamino)propyl methacrylate.

The present method requires the presence of component (D) during theaddition reaction between components (A) and (B) under catalysis bycomponent (C). Component (D) is preferably added at from 0.0001 to 1weight part per 100 weight parts component (A) and particularlypreferably at from 0.001 to 0.5 weight part per 100 weight partscomponent (A).

The present method can be run in the presence or absence of organicsolvent. Organic solvents usable for running the method are exemplifiedby aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatichydrocarbons such as hexane and heptane; ethers such as tetrahydrofuranand diethyl ether; ketones such as acetone and methyl ethyl ketone; andesters such as ethyl acetate and butyl acetate.

The present method can be run at room temperature, but is preferably runat temperatures of at least 30° C. in order to obtain good reactionrates. In addition, since the (meth)acryloxy-functional organosiliconcompounds readily polymerize and gel at high temperatures, the reactiontemperature preferably does not exceed 100° C. and more preferably is inthe range from 30° C. to 90° C.

The reaction mixture afforded by the present method can be purified bydistillation directly as obtained upon completion of the reaction. Forthis distillation the known radical-polymerization inhibitors, e.g.,hindered phenol compounds, amine compounds, quinone compounds, oxygen,etc., can be added to the reaction mixture.

The invention will be explained below through working examples, in which% indicates weight%.

EXAMPLE 1

60.0 g (0.48 mol) Allyl methacrylate, 0.04 g chloroplatinicacid/divinyltetramethyldisiloxane complex (2.7 ppm platinum metal basedon the weight of allyl methacrylate), and 0.0046 g (2.4×10⁻⁵ mol)(N,N-diethylamino)ethyl methacrylate were introduced into a 300 mLfour-neck flask equipped with a condenser, stirrer, thermometer, andaddition funnel. The temperature in the flask was brought to 70° C. and70.9 g (0.52 mol) trichlorosilane was gradually added dropwise. Afterthe completion of addition, the reaction was stirred for an additional 1hour while maintaining the reaction temperature at 70° C. This yielded119.2 g of a reaction mixture.

The reaction mixture was re-introduced into a four-neck flask, thetemperature was brought to 70° C., and 48 g methanol were graduallyadded dropwise. After the completion of addition, the hydrogen chloridewas removed under reduced pressure to give 107.3 g (yield =82%) of areaction product. Analysis of this reaction product by infraredabsorption spectroscopy and nuclear magnetic resonance spectroscopyconfirmed it to be γ-methacryloxypropyltrimethoxysilane.

Analysis of the reaction by-product in this reaction product by ionchromatography showed that only 20 weight-ppm methacrylic acid waspresent in the reaction product.

EXAMPLE 2

60.0 g (0.48 mol) Allyl methacrylate, 0.04 g (2.7 ppm) chloroplatinicacid/divinyltetramethyldisiloxane complex, and 0.0039 g (2.4×10⁻⁵ mol)(N,N-diethylamino)ethyl methacrylate were introduced into a 300-mLfour-neck flask equipped with a condenser, stirrer, thermometer, andaddition funnel. The temperature in the flask was brought to 90° C. and70.9 g (0.52 mol) trichlorosilane were gradually added dropwise. Afterthe completion of addition, the reaction was stirred for an additional 1hour while maintaining the reaction temperature at 90° C. This yielded121.0 g of a reaction mixture.

The reaction mixture was re-introduced into a four-neck flask; thetemperature was brought to 90° C.; and 48.9 g methanol were graduallyadded dropwise. After the completion of addition, the hydrogen chloridewas removed under reduced pressure to give 109.0 g (yield =83%) of areaction product. Analysis of this reaction product by infraredabsorption spectroscopy and nuclear magnetic resonance spectroscopyconfirmed it to be γ-methacryloxypropyltrimethoxysilane.

Analysis of the reaction by-product in this reaction product by ionchromatography showed that only 25 weight-ppm methacrylic acid waspresent in the reaction product.

Comparative example 1

An addition reaction was run as in Example 1, but in this case withoutthe addition of the (N,N-diethylamino)ethyl methacrylate that was usedin Example 1. 105.8 g (yield =81%) reaction product was obtained.Analysis of this reaction product by infrared absorption spectroscopyand nuclear magnetic resonance spectroscopy confirmed it to beγ-methacryloxypropyltrimethoxysilane.

Analysis of the reaction by-product in this reaction product by ionchromatography showed that 1,105 weight-ppm methacrylic acid was presentin the reaction product.

Comparative example 2

An addition reaction was run as in Example 2, but in this case withoutthe addition of the (N,Ndiethylamino)ethyl methacrylate that was used inExample 2. In this case, the reaction product lost fluidity andconverted to a gel 30 minutes after the start of the dropwise additionof the trichlorosilane.

We claim:
 1. A method for the preparation of acryloxy-functional ormethacryloxy-functional organosilicon compounds comprising the additionreaction between(A) an acrylate ester or methacrylate ester of analiphatically unsaturated alcohol and (B) a SiH-functional organosiliconcompound in the presence of (C) a hydrosilylation-reaction catalyst, and(D) a compound described by general formula ##STR5## where A is a(N,N-dialkylamino)alkyl and R is a monovalent hydrocarbon group or ahydrogen atom.
 2. A method according to claim 1, where the quantity ofcomponent (D) is from 0.0001 to 1 weight part per 100 weight parts ofcomponent (A).
 3. A method according to claim 1, where the quantity ofcomponent (D) is from 0.001 to 0.5 weight part per 100 weight parts ofcomponent (A).
 4. A method according to claim 1, where component (A) isan acrylate ester of an aliphatically unsaturated alcohol selected froma group consisting of allyl acrylate, hexenyl acrylate, allyloxethylacrylate, and 4-vinylphenyl acrylate.
 5. A method according to claim 1,where component (A) is allyl acrylate.
 6. A method according to claim 1,where component (A) is a methacrylate ester of an aliphaticallyunsaturated alcohol selected from a group consisting of allylmethacrylate, hexenyl methacrylate, allyloxyethyl methacrylate, and4-vinylphenyl methacrylate.
 7. A method according to claim 1, wherecomponent (A) is allyl methacrylate.
 8. A method according to claim 1,where component (B) is selected from a group consisting oftrichlorosilane, methyldichlorosilane, dimethylchlorosilane,trimethoxysilane, methyldimethoxysilane, dimethylmethoxysilane,pentamethyldisiloxane, and 1,1,2,2-tetramethyldisiloxane.
 9. A methodaccording to claim 1, where component (B) is trichlorosilane.
 10. Amethod according to claim 1, where component (C) is a platinum catalystselected from the group consisting of alcohol solutions ofchloroplatinic acid, platinum-olefin complexes, and platinum complexeswith vinyl-functional siloxane.
 11. A method according to claim 1, wherecomponent (D) is selected from the group consisting of by(N,N-dimethylamino)ethyl acrylate, (N,N-diethylamino)ethyl acrylate,(N,N-dimethylamino)propyl acrylate, (N,N-dimethylamino)ethylmethacrylate, (N,N-diethylamino)ethyl methacrylate, and(N,N-dimethylamino)propyl methacrylate.
 12. A method according to claim1, where component (D) is (N,N-diethylamino)ethyl methacrylate.
 13. Amethod according to claim 1, where the addition reaction is run at atemperature in the range of from 30° C. to 90° C.
 14. A method accordingto claim 1, where component (A) is allyl methacrylate, component (B) istrichlorosilane, and component (D) is (N,N-diethylamino)ethylmethacrylate.
 15. A method according to claim 1, where R is methyl.